This application is based upon, claims the benefit of priority of, and incorporates by reference the contents of prior Japanese Patent Application No. 2001-240225, filed Aug. 8, 2001.
1. Technical Field of the Invention
The present invention relates to a heating apparatus for an electric vehicle and a hybrid vehicle, and more particularly, to a heat source apparatus such as an electric heater for heating water.
2. Description of Related Art
In JP-A-10-287123, water is heated by a heat source apparatus in which a coil-shape electric heater is disposed in a hot water tank that stores hot water. The heated water (hot water) is circulated into a heat exchanger, where heat-exchange is performed between the hot water and forced air. The heated air is supplied to a passenger compartment, thereby performing heating operation in an electric vehicle.
However, in the conventional apparatus, since a hot water tank for storing hot water is used as a heat source apparatus, a lot of space is required to store the apparatus. In an electric vehicle which includes many parts, there is not a lot of space for setting the conventional apparatus. Further, since a large amount of water is required to be heated by a single electric heater, heating efficiency is low, and a long time is required for increasing the temperature of the water.
The present invention solves the above-described problem. In one aspect of the invention, a hot-water heating apparatus includes a heat source apparatus constructed by multiple, stacked, flat heat conductors. Further, a communication pipe that contains water as a heat medium, and an electric heater, are arranged in proximity to each other in rows. Additionally, both are embedded in a heat conductor metal, thereby forming each flat heat conductor. The communication pipes in the multiple heat conductors are connected in series.
Accordingly, the heat source apparatus, constructed as an assembly of flat heat conductors, is compact and does not require a wide space or a lot of space for installation. Further, the communication pipe and the electric heater are located proximate to each other and embedded in the heat conductor metal in a row-like arrangement. The communication pipes in different heat conductor metals are connected to each other in series. Therefore, water flowing in the communication pipes is heated rapidly, and heating efficiency is extremely high.
Continuing, each of the communication pipes and the electric heaters is formed in a U-shape, and the electric heater is disposed inside the U-shaped loop or perimeter of the communication pipe in each heat conductor metal. Therefore, although each heat conductor is compact, production cost is reduced by making a length of the electric heater as short as possible. At the same time, heating efficiency is improved by making a heat conduction distance as long as possible. Here, the heat conduction distance corresponds to a length along the U-shaped electric heater.
Heat insulation clearance is provided between neighboring heat conductors. This prevents heat conduction therebetween and ensures uniform temperature distribution of each heat conductor. Finally, each heat conductor includes a superheating prevention device to prevent each heat conductor from melting.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.